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1030 Poster Impact of a micro multileaf collimator on stereotactic radiotherapy of uveal melanoma
$302 Friday/Saturday, 20-21 September 2002
1030
Poster
Impact of a micro multileaf collimator on stereotactic radiot h e r a p y of uveal melanoma D. Georq 1, K. Dieckmann 1, J. Bogner 1, M. Zehetmayer 2, R. Poetter 1
Posters
groups. Conclusion: Adding a 1-mm margin to G i V in patients treated with radiosurgery increases significantly the probability of metastasis control without increasing side effects.
1AKH Vienna, Dept. of Radiotherapy and Radiobiology, Vienna, Austria 2AKH Vienna, Dept. of Ophthalmology, Vienna, Austria
1032 Poster A n a l y s i s o f p a t i e n t s w i t h high grade gliomas treated with the utilization o f a mutual-information based CT-MRI image
Purpose: To evaluate the impact of a micro-multileaf collimator (mMLC) on linac based stereotactic radiotherapy (SRT) of uveal melanoma by comparing circular arc with static conformal, dynamic arc and intensity modulated SRT. Materials and Methods: 40 uveal melanoma patients are selected from about 100 patients treated with SRT since 1996. For each patient four treatment plans (BrainSCAN XL, V5.0) are made: conventional arc, static conformal, dynamic arc plan, and IMRT. The goal of treatment planning is to fully encompass the PTV by the 80% isodose while minimizing doses to the optic nerve and lens. The following parameters are evaluated: target conformity, target homogeneity, ratio of the target volume and 50% isodose volume, normal tissue receiving doses _> 80%, 50% and 20%, CNS volume irradiated to doses > 20%, optical nerve volume irradiated > 50%, Dmax of the lens and lens volume receiving doses > 20%, and the number of monitor units (MU) necessary to deliver the prescribed dose. Results: PTVs range from 0.68 to 4.90 cm = (mean 1.97+0.97 cm~). The average reduction of the prescription isodose volume is 1-1.5 cm ~ for conformal (range 2.6-0.3 cm~), dynamic arc (range 2.5-0.3 cm~), and IMRT plans (range 3.9-0.1 cm~) compared to conventional arc therapy. CNS volumes irradiated to doses _> 20% are smallest for conventional or dynamic arc treatments. Average target dose homogeneity values are 1.74+0.50 for arc, 1.27+0.02 for static mMLC, 1.26+0.01 for dynamic arc, and 1.15_+.0.03 for IMRT plans. IMRT helps to reduce doses to the lens but does not provide an advantage for optical nerve sparing. When applying IMRT the MU increase by -1/3 compared to static mMLC based SRT. MU are lowest for dynamic arc treatments, Conclusion: Conformal mMLC and dynamic arc SRT are the treatment options of choice for linac based SRT of uveal melanoma. They presents dosimetdc advantages while being simultaneously highly efficient in treatment planning and delivery.
fusion program B. Lally, N. Yue, D. Fischer, J. Kimmett, J. Picone, J. Knisely Yale University, Therapeutic Radiology, New Haven, CT, U.S.A.
1031
Poster
RadioSurgery for brain metastasis: impact of CTV on local control G. Noel 1, J.M. Simon I, C.-A. Va/ery2, P. Comu 2, G. Boisserie 1, D. Hasboun 3, D. Ledu 1, B. Tep 1, J.-Y. De/attre4, J.-J. Mazeron I 1piti~ Salp@tri~re Hospital, Radiotherapy, Pads; France 2piti~ Salp~tri~re Hospital, Neurosurgery, Paris, France 3piti~ Salpetri~re Hospital, Neuroradiology, Pads, France 4piti~ Salp~tri~re Hospital, Neurology, Paris, France Purpose: Purpose of the present analysis was to assess whether adding a 1-mm safety margin to GTV increases the control rate of brain metastasis treated with radiosurgery (RS) in a population of consecutive patients. Patients and methods: All the patients had one or two brain metastases, 30 mm or less in diameter, and only one isocentre was used for RS. There were 23 females and 38 males. Median age was 54 years (34-76). Median Karnofsky performance status (KPS) was 80 (60-100). At time of radiosurgery, 23 patients had their extracranial tumour controlled and 38 had a progressive systemic disease. Thirty-eight patients were treated up-front with only RS. Twenty-three patients were treated for relapse or progression more than 2 months after whole brain radiotherapy. From January 1994 to July 1995, CTV was GTV without any margin (33 metastases). From August 1995 to August 2000, CTV was defined as GTV plus a 1-mm margin (45 metastases). Patients were given 20 Gy at the isocenter and 14 Gy at the limit of CTV. Results: Median follow-up was 10.5 months (1-45). Mean minimum dose delivered to GTV was 14.6 Gy in the Group without margin and 16.8 Gy in the group with margin (p < 0.0001). Overall, response of 11 metastases was never assessed because patients died before the first follow-up. Ten metastases recurred, eight in the group treated without margin and, two in the group treated with one (p = 0.01 ). Two-year local control rates were 50.7 ± 12.7% and 89.7 ± 7.4% (p = 0.008), respectively. Univariate analysis showed that the group of treatment (p = 0.008) and the tumor volume (p = 0.009) were prognostic factors for local control. In multivariate analysis, only group of treatment was an independent prognostic factor for local control (p = 0.04, RR: 5,8, 95% CI [1.08-31.13]). There were no differences, neither in overall survival rate nor in early and late side effects between the two
Purpose: To evaluate survival for patients with high grade gliomas treated with 3-D conformal radiotherapy using a mutual-information based image fusion program (MIBIFP) developed at our institution. We sought to determine the accuracy of our conedown (CD) treatment by examining patterns of failure. Methods: Between 1/1998 and 9/2001, 47 consecutive patients with highgrade gtiomas were treated with 3DCRT. The treatment planning involved a CT-MRI image fusion to identify the tumor volumes. GTVs were determined directly from the T2 and TIC weighted reformatted MR scans., The initial PTV was the T2 weighted GTV with a margin of 2 cm except where anatomic barriers to spread existed. For CD, the PTV included the T1C weighted GTV and 1.5-2 cm margins. In cases where these volumes would include critical radiosensitive structures, the margins were decreased. In follow-up, failure was considered to be radiographically documented recurrence of tumor. The MR images at the time of failure were then fused with the original treatment planning CT, again using the MIBIFP. The superimposition of the original plan upon the MR study documented the minimum isodose surface volume (ISV) encompassing the failure site. Results: As of 3/2002 the overall 1 yr. survival rate was 84%. The median survival has not yet been reached. The median disease free survival was 13.1 months. There were 23 disease failures documented including 19 patients who had follow-up imaging available for MIBIFP. Five patients had no field reduction for CD. Examination of the patterns of failure for the CD showed that 13 patients failed within the volume encompassed by the 90% ISV. Three patient failed within the 80% ISV. Two patients failed within the 90% ISV and also failed in the contralateral hemisphere or spine. A single patient failed only in the contralateral hemisphere without failure at the original tumor site. The failures for two of the patients who failed within the 80% ISV for the CD were within the 90% SVI for the initial PTV. The remainder of the failure patterns was identical between the initial PTV and CD. Conclusions: Our results show that MIBIFP is a valuable aid in accurate determination of the volumes to treat. Further analysis of our patterns of failure may allow a reduction in the initial PTV, which would allow for close escalation to the tumor. Further analysis of patterns of failure may help to determine appropriate margins on GTV for PTV determination. 1033
Poster
Long-term results of surgery and post-operative radiation therapy in the curative management of intracranial ependymoma D.B. Mansur I, J.M. Micha/ski 1, J.G. Ojemann2, T.S. Park2, L. LuchtmanJones 3, K.M. Rich2, P. 14I.Grigsby 1, V. Rajaram 4, A. Perry4, J.R. Simpson 1 1
n
Washingto University, Radiation Oncology, Saint Louis, Missouri, U.S.A. 2Washington University, Neurosurgery, Saint Louis, Missouri, U.S.A. 3Washington University, Pediatric Hematology and Oncology, Saint Louis, Missouri, U.S.A. 4Washington University, Neuropathology, Saint Louis, Missouri, U.S.A. Purpose: To determine the outcome of intracranial ependymoma patients treated with surgery and post-operative radiation therapy (RT). Materials and Methods: Between 1964 and 2000, 63 patients with intracranial ependymoma (n=44) or anaplastic ependymoma (n=19) were treated with surgery and post-operative RT with curative intent. The median age of patients was 10.8 years (range 7 months to 76 years). The extent of resection included gross total (n=15), subtotal (n=44), biopsy alone (n=l), and unknown (n=3). No patient had craniospinal seeding or other disseminated disease at the time of RT. The median RT dose was 50.4 Gy. Thirteen patients received prophylactic RT to the craniospinal axis. However, treatment philosophy evolved over the time period, and the majority of patients (n=50) were treated to local fields. Results: The median follow-up of surviving patients is 13.0 years. The 5 and 10 year overall survival (OS) for all patients is 66.0% and 53.1%, respectively. The 5 and 10 year disease free survival (DFS) for all patients is 56.8% and 48.2%, respectively. Those patients with anaplastic ependymo-
1030
Poster
Impact of a micro multileaf collimator on stereotactic radiot h e r a p y of uveal melanoma D. Georq 1, K. Dieckmann 1, J. Bogner 1, M. Zehetmayer 2, R. Poetter 1
Posters
groups. Conclusion: Adding a 1-mm margin to G i V in patients treated with radiosurgery increases significantly the probability of metastasis control without increasing side effects.
1AKH Vienna, Dept. of Radiotherapy and Radiobiology, Vienna, Austria 2AKH Vienna, Dept. of Ophthalmology, Vienna, Austria
1032 Poster A n a l y s i s o f p a t i e n t s w i t h high grade gliomas treated with the utilization o f a mutual-information based CT-MRI image
Purpose: To evaluate the impact of a micro-multileaf collimator (mMLC) on linac based stereotactic radiotherapy (SRT) of uveal melanoma by comparing circular arc with static conformal, dynamic arc and intensity modulated SRT. Materials and Methods: 40 uveal melanoma patients are selected from about 100 patients treated with SRT since 1996. For each patient four treatment plans (BrainSCAN XL, V5.0) are made: conventional arc, static conformal, dynamic arc plan, and IMRT. The goal of treatment planning is to fully encompass the PTV by the 80% isodose while minimizing doses to the optic nerve and lens. The following parameters are evaluated: target conformity, target homogeneity, ratio of the target volume and 50% isodose volume, normal tissue receiving doses _> 80%, 50% and 20%, CNS volume irradiated to doses > 20%, optical nerve volume irradiated > 50%, Dmax of the lens and lens volume receiving doses > 20%, and the number of monitor units (MU) necessary to deliver the prescribed dose. Results: PTVs range from 0.68 to 4.90 cm = (mean 1.97+0.97 cm~). The average reduction of the prescription isodose volume is 1-1.5 cm ~ for conformal (range 2.6-0.3 cm~), dynamic arc (range 2.5-0.3 cm~), and IMRT plans (range 3.9-0.1 cm~) compared to conventional arc therapy. CNS volumes irradiated to doses _> 20% are smallest for conventional or dynamic arc treatments. Average target dose homogeneity values are 1.74+0.50 for arc, 1.27+0.02 for static mMLC, 1.26+0.01 for dynamic arc, and 1.15_+.0.03 for IMRT plans. IMRT helps to reduce doses to the lens but does not provide an advantage for optical nerve sparing. When applying IMRT the MU increase by -1/3 compared to static mMLC based SRT. MU are lowest for dynamic arc treatments, Conclusion: Conformal mMLC and dynamic arc SRT are the treatment options of choice for linac based SRT of uveal melanoma. They presents dosimetdc advantages while being simultaneously highly efficient in treatment planning and delivery.
fusion program B. Lally, N. Yue, D. Fischer, J. Kimmett, J. Picone, J. Knisely Yale University, Therapeutic Radiology, New Haven, CT, U.S.A.
1031
Poster
RadioSurgery for brain metastasis: impact of CTV on local control G. Noel 1, J.M. Simon I, C.-A. Va/ery2, P. Comu 2, G. Boisserie 1, D. Hasboun 3, D. Ledu 1, B. Tep 1, J.-Y. De/attre4, J.-J. Mazeron I 1piti~ Salp@tri~re Hospital, Radiotherapy, Pads; France 2piti~ Salp~tri~re Hospital, Neurosurgery, Paris, France 3piti~ Salpetri~re Hospital, Neuroradiology, Pads, France 4piti~ Salp~tri~re Hospital, Neurology, Paris, France Purpose: Purpose of the present analysis was to assess whether adding a 1-mm safety margin to GTV increases the control rate of brain metastasis treated with radiosurgery (RS) in a population of consecutive patients. Patients and methods: All the patients had one or two brain metastases, 30 mm or less in diameter, and only one isocentre was used for RS. There were 23 females and 38 males. Median age was 54 years (34-76). Median Karnofsky performance status (KPS) was 80 (60-100). At time of radiosurgery, 23 patients had their extracranial tumour controlled and 38 had a progressive systemic disease. Thirty-eight patients were treated up-front with only RS. Twenty-three patients were treated for relapse or progression more than 2 months after whole brain radiotherapy. From January 1994 to July 1995, CTV was GTV without any margin (33 metastases). From August 1995 to August 2000, CTV was defined as GTV plus a 1-mm margin (45 metastases). Patients were given 20 Gy at the isocenter and 14 Gy at the limit of CTV. Results: Median follow-up was 10.5 months (1-45). Mean minimum dose delivered to GTV was 14.6 Gy in the Group without margin and 16.8 Gy in the group with margin (p < 0.0001). Overall, response of 11 metastases was never assessed because patients died before the first follow-up. Ten metastases recurred, eight in the group treated without margin and, two in the group treated with one (p = 0.01 ). Two-year local control rates were 50.7 ± 12.7% and 89.7 ± 7.4% (p = 0.008), respectively. Univariate analysis showed that the group of treatment (p = 0.008) and the tumor volume (p = 0.009) were prognostic factors for local control. In multivariate analysis, only group of treatment was an independent prognostic factor for local control (p = 0.04, RR: 5,8, 95% CI [1.08-31.13]). There were no differences, neither in overall survival rate nor in early and late side effects between the two
Purpose: To evaluate survival for patients with high grade gliomas treated with 3-D conformal radiotherapy using a mutual-information based image fusion program (MIBIFP) developed at our institution. We sought to determine the accuracy of our conedown (CD) treatment by examining patterns of failure. Methods: Between 1/1998 and 9/2001, 47 consecutive patients with highgrade gtiomas were treated with 3DCRT. The treatment planning involved a CT-MRI image fusion to identify the tumor volumes. GTVs were determined directly from the T2 and TIC weighted reformatted MR scans., The initial PTV was the T2 weighted GTV with a margin of 2 cm except where anatomic barriers to spread existed. For CD, the PTV included the T1C weighted GTV and 1.5-2 cm margins. In cases where these volumes would include critical radiosensitive structures, the margins were decreased. In follow-up, failure was considered to be radiographically documented recurrence of tumor. The MR images at the time of failure were then fused with the original treatment planning CT, again using the MIBIFP. The superimposition of the original plan upon the MR study documented the minimum isodose surface volume (ISV) encompassing the failure site. Results: As of 3/2002 the overall 1 yr. survival rate was 84%. The median survival has not yet been reached. The median disease free survival was 13.1 months. There were 23 disease failures documented including 19 patients who had follow-up imaging available for MIBIFP. Five patients had no field reduction for CD. Examination of the patterns of failure for the CD showed that 13 patients failed within the volume encompassed by the 90% ISV. Three patient failed within the 80% ISV. Two patients failed within the 90% ISV and also failed in the contralateral hemisphere or spine. A single patient failed only in the contralateral hemisphere without failure at the original tumor site. The failures for two of the patients who failed within the 80% ISV for the CD were within the 90% SVI for the initial PTV. The remainder of the failure patterns was identical between the initial PTV and CD. Conclusions: Our results show that MIBIFP is a valuable aid in accurate determination of the volumes to treat. Further analysis of our patterns of failure may allow a reduction in the initial PTV, which would allow for close escalation to the tumor. Further analysis of patterns of failure may help to determine appropriate margins on GTV for PTV determination. 1033
Poster
Long-term results of surgery and post-operative radiation therapy in the curative management of intracranial ependymoma D.B. Mansur I, J.M. Micha/ski 1, J.G. Ojemann2, T.S. Park2, L. LuchtmanJones 3, K.M. Rich2, P. 14I.Grigsby 1, V. Rajaram 4, A. Perry4, J.R. Simpson 1 1
n
Washingto University, Radiation Oncology, Saint Louis, Missouri, U.S.A. 2Washington University, Neurosurgery, Saint Louis, Missouri, U.S.A. 3Washington University, Pediatric Hematology and Oncology, Saint Louis, Missouri, U.S.A. 4Washington University, Neuropathology, Saint Louis, Missouri, U.S.A. Purpose: To determine the outcome of intracranial ependymoma patients treated with surgery and post-operative radiation therapy (RT). Materials and Methods: Between 1964 and 2000, 63 patients with intracranial ependymoma (n=44) or anaplastic ependymoma (n=19) were treated with surgery and post-operative RT with curative intent. The median age of patients was 10.8 years (range 7 months to 76 years). The extent of resection included gross total (n=15), subtotal (n=44), biopsy alone (n=l), and unknown (n=3). No patient had craniospinal seeding or other disseminated disease at the time of RT. The median RT dose was 50.4 Gy. Thirteen patients received prophylactic RT to the craniospinal axis. However, treatment philosophy evolved over the time period, and the majority of patients (n=50) were treated to local fields. Results: The median follow-up of surviving patients is 13.0 years. The 5 and 10 year overall survival (OS) for all patients is 66.0% and 53.1%, respectively. The 5 and 10 year disease free survival (DFS) for all patients is 56.8% and 48.2%, respectively. Those patients with anaplastic ependymo-